Expander for pistons



June 30, 1936. J ALLEN 2,045,819

' EXPANDER FOR PISTONS Filed Jan. 6, 1936 Patented June 30, 1936 UNITED" STATES- PATENT OFFICE fflsrohs I I V I Application January 6, 1936, Serial No. 57355 501mm. (01. soc- 12) The object of my invention is to provide a novel expander for slotted skirts of pistons, which can be made at a. small cost and which can be readily installed by small shops which have limited equipment. It is further an object of my invention to provide an expander having novel means for securing it to the skirt of a piston whereby the device will not score the block and whereby it will tend to lock more firmly in place under stress of operation, rather than towork loose. I attain these and other objects of my invention by the means illustrated in the accompanying drawing, in which- Figure l is a side elevation of a piston with my expander applied to it, portions of the expander which are concealed by the piston being shown in dotted lines; Fig. 2 is a: horizontal section on line 2-2 of Fig. 1;

Fig. 3 is a perspective detail view of one of the rivets used;

Fig. 4 is a frontplan view of the expander wire showing the position it assumes when it opera tively engages with the rivets; and Fig. 5 is a front plan view of the expander wire in its open expanded position, the open position oi. the wire being slightly exaggerated.

Like numerals designate like parts in each of the several "views.

Referring to the accompanying drawing; i designates'the piston skirt having the usual slot 3 and the customary longitudinal diagonally disposed slot 2. d designates apertures or openings drilled in the piston skirt at like spaced points from the longitudinal slot and at approximately the central portion of said skirt to permit of its being expanded by a single expander. I provide rivets 5, which are driven into the openings 5 until the bottoms of the heads t are approximately aligned with the inner surface of the piston wall.

A one-quarter inch bit is used to countersink slightly the outer portions of the apertures t, and the rivets 5 are pushed in from the inside of the piston wall and then riveted in place. Then, with a file the ends may be smoothed-down to the surface oi the piston.

I form the expander element of a single strand of wire bent on itself at its central portion 1 and having V-shaped arms 8 extending from said bend i to the bulged portions t, and thence continuing with inwardly bent portions it adapted to engage the heads 6 of rivets 5 and terminating in ofiset ends ii substantially parallel with the bulges t, as shown best in Fig. 4.

In applying the expander-it is caught with a pair of pliers and pinched together sufllciently to permit of engaging inwardly. the recessed portions I0 against the inside surfaces of the heads 6 of the rivets.

It will be noted by reference to Fig. 2 that the expander seats snugly against thev inside wall of the piston. This disposition of the expander is of importance as it is thus disposed in a position where it is not liable to contact with moving parts of the piston rod or associated parts. In this respect it is more advantageous than expanders of U-shape, for the reason that the V- shape form permits it to lie close to the wall of the piston from one end to the other of the spring, instead of extending straight -across at its bent portion, as is necessarily'true of expanders of U-shape. In other words, in the case of expanders of the U-shape type each side of the U would lie against the wall, but the central portion which extended acrossthe slot of the piston skirt would necessarily stand out farther from the wall than is true of my V-type expander. Furthermore, some pistons on the inside have a thickened portion on each side of the slot where it comes up to a taper, thus causing a wide expander, such as the U-shape type, to stand out still farther from the inside wall oi the piston skirt. My expander has a further advantage over expanders of the U-shape type, in that as the inwardly bent portion it rests against the slanting surface of the head it the jar of operation tends to more tightly seat the expander in place, as it has a tendency to work in toward the inner wall of the piston. There is also less danger of scoring the block by use of the rivets d, which are of a soft metal, than is true of piston expanders in which the ends of the spring wire does extend through apertures in the piston wall. In the case of my rivets they will under no circumstances work in and score the block. No special tool is required to make the installation. The device may be installed with the tools used by the average small shop.

I provide three different sizes oi wires, of which the expander is made, which range intensionirom approximately '90 pounds to approximately pounds, and which tension is sufflcient so that only one expander is required for each piston.

The looseness of and the amount of tension required to expand each piston determines the size of expander to be used. The'three sizes of expanders are interchangeable, detachably engaging the inner portions of the slanting rivet heads without alterations.

My expander has a further advantage over other types of expanders due to its weight of one-eighth to three-sixteenths of an ounce, therefore eliminating the chances of a high speed vibration in motors caused by adding weight to and unbalancing the pistons.

Another advantage over other types of expanders is that the complete installation of my expander may be made in all split sldrt pistons without disassembling piston rod and piston pin from the piston;

What I claim is:

1. As a new article of manufacture for use with a piston having a slotted skirt, an expander adapted to expand the slotted skirt of the piston and comprising a wire formed in substantially V-shape, and having its end portions formed with opposite bulged portions, successive opposite integral bent portions, and ofiset ends aligned with the bulged portions, the point of the V having its portions closely bent to resist expansion and to cause the expander to lie close to the skirt of the piston when operatively connected thereto.

2; In combination with a slotted piston skirthaving rivets driven into spacedjapertures in the piston wall from the inside and having the bottoms of their. beveled heads flush with the inside wall of the piston skirt, and a piston expander comprising a wire formed in substantially V-shape and having its end portions bent to engage the beveled riveted heads, to cause the piston expander to lie snugly against the inside wall of the piston skirt.

3. In combination with a piston having a 1ongitudinally slotted skirt, said skirt having a pair .of openings drilled at spaced portions in an approximately median plane of the slotted portion of the'skirted piston and slightly countersunk, rivets riveted in said apertures with beveled heads disposed inside the piston skirt and substantially flush with the inner wall thereof,- and a V-shaped wire expander having opposite inwardly bent portions near its outer free ends engageable against the inside surfaces of the beveled heads of said rivets to exert expansive force on the slotted. piston skirt and to urge the expander toward the piston skirt.

" 4. In combination with a piston having a longitudinally slotted skirt, and having members having beveled'heads projecting within and secured to the skirt at opposite spaced portions from said slot, a V-shaped wire expander having its free ends shaped to engage the inner'sur THOMAS J. ALLEN. 

